Introduction to Control Unit 7'6

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Introduction to ControlUnit 7.6
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Control technology

• The use of control systems to switch output
  devices on and off
• In a sequence
• OR
• In response to an input device like light, sound

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Control systems

• Control systems make use of electronic circuits.
• Events are programmed onto the computer then
  downloaded onto a chip
• Events must be programmed in the right order
• Some examples of control systems-
• An automatic door
• An escalator that starts when someone walks onto
  it
• A washing machine

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Writing control procedures - Keywords

• Procedure A sequence of instructions
• Automatic Something that happens without the
  help of a human being
• Program A set of instructions for a computer
• Go to task 1

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Task 1

• Watch the video
• Write a sequence of instructions for someone who
  has never ridden a bike before to follow

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Automated systems

• Control systems make our lives easier
• An automated system keeps track of a fridges
  temperature rather than a person having to check
  it every 5 minutes
• However a robot performing a surgical operation
  would not be a good idea.

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Task 2

• What happens when the car reaches the barrier?
• Record the sequence of events after the car
  reaches the barrier use the flowchart

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Flowchart
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Control interface

• A control interface is a box that allows a
  computer to control and power output devices
• It can detect the state of input devices and send
  the information to the computer

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Input/output devices

• Control systems depend on an input to start, stop
  or modify the process
• Two types of input devices-
• Digital input Where the input device is on or
  off, such as a light switch
• Analogue input Where a range of values are sent
  to the computer from devices such as sensors for
  temperature, light and sound

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Task 3

• Write down the sequence of events
• What triggers the barrier to rise?
• What triggers the barrier to lower?
• What additional safety devices do you think are
  incorporated into the system?